A mixer circuit is a type of multiplier circuit that provides frequency translation for two or more signals. For example, in a radio receiver, a mixer circuit is used to translate an RF (radio frequency) signal to an IF (intermediate frequency) signal. In an integrated circuit mixer, the signals to be mixed are applied to the gates of input transistors. The output is a multiplication of the two input signals. Designers of high frequency mixer circuits have been faced with the problem of providing a relatively small and easy to implement mixer circuit that provides highly linear operation at low power supply voltages (e. g. 1.0–1.5 volts).
Therefore, it is desirable to provide an integrated circuit device for mixing two signals that is small and easy to implement, yet provides highly linear operation at low voltage.